Three-point microbend size effects for pure Ni foils

The three-point microbend tests are performed for the pure Ni foils with different thicknesses. The deflection and load are measured by employing the sequence pulse counting method and a high sensitive micro load-sensor, respectively. All experimental results are analyzed using couple stress theory by Fleck and Hutchinson in which only rotation gradient is considered. Based on the plane-strain model we have derived the differential equations and boundary conditions, which include the effect of couple stress. The differential equations are solved by the Runge-Kutta method. The numerical results are compared with the experimental data. There is no any fitting parameter in the present theoretical calculation. All material parameters are taken from the experimental measurements. The length scale is taken from the work of Stolken and Evans^[2]. The present theoretical predictions are in good agreement with the experimental data.